Numerical simulation of frequency-dependent Q effect in VTI viscoelastic media based on the fractional Zener model
Viscoelasticity is a basic property of earth media.When seismic waves propagate through it,they usually experience amplitude reduction and velocity dispersion,which changes the energy and traveltime,and finally affects accurate imaging and interpretation of seismic data.Therefore,it is essential to study seismic wave propagation in viscoelastic media.Currently,the Constant-Q(frequency-independent)Model(CQM)is mainly used to characterize seismic wave propagation in earth media,which is inconsistent with the frequency-dependent Q effect observed in high-temperature,high-pressure,or fluid-containing media.Based on the Fractional Zener Model(FZM),this study investigates the frequency dependence of Q with different fractional orders.Considering the anisotropy of velocity and attenuation,we derive the FZM viscoelastic wave equation and propose the frequency-dependent Q simulation method in VTI media.Numerical examples suggest that when the frequency dependence is weak,the FZM and CQM results are similar.Otherwise,their results have obvious differences in modeling results.
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维普
